Silver dye bleach process using bleachable nitro-aryl dyes

ABSTRACT

THE COMPOUNDS ARE OF THE CLASS OF NOBEL NITRO DYES, USEFUL IN A SLVER DYE BLEACHING METHOD OF COLOR PHOTOGRAPHY, HAVING AS THE CHROMOPHORE A NITRO GROUP, AND AS THE AUXOCHROME -OX (WHEREIN X REPRESENTS A HYDROGEN ATOM, AN ALKALI META OR 1/2 CALCIUM AND AMMONIUM) OR -NHY (WHEREIN Y REPRESENTS A HYDROGEN ATOM, A LOWER ALKYL GROUP, A SUBSTITUTED ALKYL GROUP, A CYCLIC ALKYL GROUP, AN ARYL GROUP AND A SUBSTITUTED ARYL GROUP), AND THE -NHY MAY FORM A RING TOGETHER WIT -O- OR -N-R (WHEREIN R IS AN ARYL GROUP OR A SUBSTITUTED ARYL GROUP).

United States Patent ()flice 3,552,960 Patented Jan. 5, 1971 3,552,960SILVER DYE BLEACH PROCESS USING BLEACHABLE NITRO-ARYL DYES Hideo Kondoand Shigeru Wata iabe, Kanagawa, Japan, ilssignors to Fuji Photo 'FilmCo., Ltd., Kanagawa,

apan I No Drawing. Filed July 19, 1967, Ser. No. 654,349 Claimspriority, application Japan, July 19, 1966,

41/47,188 Int. Cl. G03c 1/10, 5/52 US. CI. 96-20 29 Claims ABSTRACT OFTHE DISCLOSURE BACKGROUND OF THE INVENTION (1 Field of the invention Thepresent invention relates generally to a photoggraphic color process andparticularly to a process for represents a hydrogen atom, an alkalimetal, /2 calcium or ammonium) or NHY, (wherein Y represents a hydrogenatom; a lower alkyl group;'a substituted'alkyl group, such as anaminomethyl group or a hydroxyethyl group, a cyclic alkyl group; an arylgroup; or a spbstituted aryl group such as a hydroxyphenyi group or{sulfanaphthyl group) which may form fa ring together with APR (whereinR represents an aryl group or a substituted aryl group such as am'ethoxyphenyl group) which is at the ortho position to NHY.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Among thesenitro dyes apreferable dye is a nitrobenzene or a nitronaphthalene having OX or NHY(X and Y are as defined above) at the ortho-position to the nitro group.In addition, the benzene ring or the naphthalene ring may be substitutedwith at least one of the following: a n'itro group, a lower alkyl group,an

obtaining color photographs by a silver dye bleaching method. 7

(2) Description of the prior art The production of photographiccolorimages by a silver dye bleaching method is based on the fact thatcertain types of dyes are destroyed by a suitable treatment in thepresence of metallic silver. In a silver dye bleaching method, afterexposure and development, a photographic .gelatine-silver halideemulsion layer which is uniformly colored with a proper dye is processedin a bleaching bath capable of simultaneously oxidizing the silver imageformed and reducing (bleaching) the dye at the areas having the silverimages. The silver salts and remaining metallic silver are then removedto provide a reversal dye image of the initial silver image. By thisprocess, a monochromatic ir nage or a multi-color image canvbe obtained.For these purposes, there have hitherto been used azo dyes,anthraquinone dyes, indigoid dyes, and phthalocyanine dyes. 7

aryl group, a substituted aryl group such as a nitro phenyl group, anamino group, a cyano group, a halogen atom, a carboxyl group, a sulfonicacid group, SO R (vihere R represents an aryl group or a substitutedaryl group such as a nitro-phenyl group), and

R2 SO2N/ R3 I (R and R each represent a hydrogen atom, a lower alkylgroup, a substituted alkyl group such as an aminomethyl group or ahydroxyethyl group, a cyclic alkyl group, an aryl .group or asubstituted aryl group such as a hydroxyphe'nyl group). The typicalexamples of the The dye used in the silver dye bleaching method must abe one which can be easily bleached by a bleaching bath in proportion tothe amount'of photographic silver image and can also be completelybleached at the areas of maxi- :mum silver image density. In addition,the dye must have I good fastness to light. It is desirable that theindividual light. Therefore, it is desirable to provide a process of,obtaining photographic color images by a silver dye 'bleaching methodusing a dye satisfying the aforesaid conditions.

SUMMARY OF THE INVENTION The present invention is based on the discoveryof the fact that nitro dyes can be bleached by a photographic "silverimage in a step of asilver dye bleaching method.

By nitro dye is meant a dye having as the chromophore a nitro group andas the auxochrome OX (wherein X nitro dyes used in this invention areasfollows:

oooH

(1) Br NO:

00101; In dextram oline 1 6300 (IJNHR 02N i-NOz SOaNH;

Color Index Compound No. 10302 O2N NH:

-- NC CN Color Index Compound No. 10306 Color Index Compound No. 10310N02 7 NOa H .1. 7 .1

NO; NO; (5) 5 Color Index-Comp Color Index Compound No.10311 N 02 N01 7Color Index Compound No. 10345 10 v i I N(|)2 N02 (6) 3 I Color IndexCompound No. 10315 15 00101 Index Compound 10350 ONaaS- N02 I j (16)Color Index Compound No. 10385 I N02 7 N0: OzN-QNH-QSOaNa' Color IndexCompound No. 10310 I v 7 Color Index Compound No. 10370 ongomsoaiwaColor Index Compound No. 10325 N 0:

Color Index Compound No. 10380 I m 1."? W 0 J r' j v 1 NO, '31 1 C1 0 IColor Index Compound No. 10395 Color Index Compound No. 10330 i 0, v

N02 HgNO2S I v v, I I V I K (20) NH 4 Color Index Disperse Yellow 33 r(10) v .NOI

Color Index Compound No. 10335 I i l I I I v v o I H E (11) Color IndexCompound No. 10338 00101- Index Compound No. 10305 I 0, N01 f 501M N02 fI v,

OzN-QNH-Q H color Index Compound No. 10340 p01 Indox Compound No. 10400H v HsCz N071 v slbaNa I I v I Nozs-NHNHNncoom I-I5C2/ (2 Color IndxCompound No. 10405- SOaNa S OaNa 0010i Indx Compound No. 10410 v SOaNaColor Index Compound'No. 10415 N02 1 Naols O/ -NO2 l COOH Color IndexCompound No. 10425 N02 NH l NaOsS- N I g Color Index Compound No. 10430NH; NH H03S '-NOg Color Index Compound No. 10435 N02 NH NQO5S- NO2 r NHzH-C CO Color Index Compound No. 10440 Kagabu Kyokai (The OrganicSynthetic Chemical Society) and published in 1959. As disclosed therein,the method of preparing this dye is by the condensation of aniline with3-nitro-4-chlorbenzene sulfonamide.

The dyes shown by the above structures (3), (18), (19) and (212)-(28)have a brownish color hue and hence can be used as the dyes formono-chromatic lightsensitive elements, for example, the copyinglight-sensitive elements described in the specifications of BritishPats. 999,996 and 1,002,345. By exposing a silver halide emulsion layercolored by such a dye through a black and white original, developingandfixing as in a conventional silver dye bleaching method, processing thelayer in a dye bleaching bath to form a color image, and removingremaining silver, a positive copy can be obtained.

As is well known, nitro dyes have been employed for dyeing naturalfibers such as wool and cotton or artificial fibers such as acetates,polyamides, and polyesters. Many nitro dyes as well as the preparationprocesses thereof are known. 1

In the present invention, the nitro dye is used for dyeing a colloid,such as gelatin or poly-vinyl alcohol, for forming a photographic layer.In particular, the nitro dye is used as a dye for forming the yellowimage of a multiple layer light-sensitive color element such as alight-sensitive negative color element or a light-sensitive positivecolor element the image of which may be observed by transmitted light orreflected light. A colloid for forming a light-sensitive layer iscolored by the nitro dye and then mixed with a silver halide emulsion.The resulting mixture may be applied to a support as a photographiclayer. Alternately, the dye may be brought into contact with an emulsionlayer to be incorporated into the layer which consists of only theabove-mentioned colloid, such as a layer consisting only of gelatin.Furthermore, after exposure or development, the emulsion layer may becolored with the nitro dye. These nitro dyes may be used in the samemanner as conventionally employed dyes.

In the case of a water-soluble nitro dye, the dye can be mixed in agelatin solution or a photographic emulsion as an aquous solutionthereof. In the case of a waterinsoluble dye, the dye is dispersed in agelatin solution or a photographic emulsion by using a dispersing agentsuch as sodium alkylbenzene sulfonic acid. Moreover, a nitro dye solublein an organic solvent may be dissolved in an organic solvent and thesolution thus obtained may be mixed in a gelatin solution or aphotographic emulsion, or the organic solvent solution may beemulsion-dispersed in getain by using a surface active agent. Inaddition, after exposing and developing, an uncolored photographicemulsion layer may be dyed with an aqueous solution of a water-solublenitro dye. The colored layer obtained is then used, for example, as acomponent of a two or three-color system.

Suitable organic solvents are alcohols such as methanol, ethanol,ethylene glycol, a monoalkyl ether of ethylene glycol, and a monoalkylether of diethylene-glycol, esters such as ethyl acetate and butylacetate; ethers such as ethyl ether, dioxane, and tetrahydrofuran,ketones such as acetone and methylethylketone; amides such as lactamsand dialkylcarbamides; and the like. Moreover, high boiling point oilysolvents may be employed. For example, alkyl esters of phthalic acidsuch as dibutyl phthalate, dioctyl phthalate, etc., phosphoric acidesters such as triphenyl phosphate and tricresyl phosphate; alkylamidessuch as dibutyllaurylamidel and acetanilides such as N-butylacetanilide.

As the dye bleaching bath, known acid bleaching baths may be used. Thebleaching bath contains a solvent for silver such as thiourea,se-micarbazide, etc., and an alkali metal halide such as sodiumchloride, potassium bromide, etc. The bleaching bath may contain as acatalyst an accelerator used in the bleaching processing of an azo dyein a conventional silver dye bleaching method, such as anthraquinonesulfonic acid, dimethylquinoxaline, aminohydroxyphenazine, and the like.

According to the present invention, an image having utterly colorlesshighlight portions can be obtained since the nitro dye can be easilybleached and hence the bleaching can be completely conducted.

The invention will be explained in more detail by referring to thefollowing examples.

EXAMPLE 1 Into 2 ml. of tricresyl phosphate was dissolved 0.2 g. of Cl.Disperse Yellow 42 represented by aforesaid structure (21). The solutionobtained was added into 10 ml.

of a 10% aqueous gelatin solution containing 2 ml. of a 10% aqueoussolution of sodium alkyl-benzene sulfonate and subjected to dispersingby means of a homoblender. After mixing 6 g. of the dispersion with 20g. of a silver bromide photographic emulsion (containing about 30 g. ofsilver bromide per one kg. of emulsion), the resulting mixture wasapplied on a glass plate.

The light-sensitive plate was exposed through a step wedge and thendeveloped for 10 minutes in a developer having the followingcomposition.

G. N-methyl-p-aminophenol 1/2. sulfate 2 Sodium sulfite (anhydrous) 30Hydroquinone 8 Sodium carbonate (mono-hydrate) 20 Potassium bromide 4Water to make 1 liter.

The plate was then washed with water and fixed for 4 minutes in a fixingsolution having the following composition:

. G. Sodium thiosulfate (anhydrous) 350 Sodium sulfite (anhydrous) 10Water to make 1 liter.

The plate was washed with Water, hardened with a 10% aqueous solution offormaldehyde, and then washed with water again. The plate was thenprocessed for 15 minutes in a dye bleaching solution having thefollowing composition:

Thiourea-6O g.

Potassium bromide-30 g. Concentrated hydrochloric acid-.430 ml.2-amino-3-hydroxyphenazine0.01 g. Water to make 1 liter.

The plate thus bleached was then washed With water and subjected tosilver bleaching in a solution having the following composition:

Crystalline copper sulfate100 g. Concentrated hydrochloric acid-100 ml.Water to make 1 liter.

The plate was then washed with water, fixed in a fixing bath having thesame composition as shown above, washed again with water, and dried. Ayellow dye image having excellent light fastness and a lemon-yellow hueWas obtained. Bleaching of highlights was complete, and the blue opticaldensity was 0.12. This is particularly suitable as an image of a yellowcomponent in a multiple color type light-sensitive element. Forcomparison, the same procedure as above was repeated using theconventional yellow azo dye having the following structure to provide animage. The blue optical density of the highlight portion was only 0.35.

e t-Q EXAMPLE 2 The same procedure as in Example 1 was repeated using 4ml. of ethyl acetate instead of 2 ml. to tricresyl phosphate and almostidentical results were obtained.

EXAMPLE 3 By repeating the same procedure as in Example 1 While using 2ml. of dibutyl phthalate and 1 ml. of butyl acetate instead of 2 ml. oftricresyl phosphate, almost identical results were obtained.

EXAMPLE 4 EXAMPLE 5 By repeating the same procedureas in Example 1 whileusing the dye shown by structure (9) instead of Cl.

Disperse Yellow 42 in Example 1., a yellow image was obtained.

EXAMPLE 6 By repeating the same procedure as in Example 1 while usingthe dye shown by structure (11), a yellow image was obtained.

EXAMPLE 7 Into 40 m1. of water, 0.4 g. of Cl. Disperse Yellow 33 shownby structure (20) was dispersed. The dispersion was mixed with 50 g. ofa silver bromide emulsion (containing about 30 g. of silver bromide perone kg. of emulsion), and the mixture was applied to a glass plate. Thelight-sensitive plate was exposed and processed as in Example 1 toprovide a yellow wedge image.

EXAMPLE 8 Into 100 ml. of water, one g. of Cl. Acid Yellow shown bystructure (7) was dissolved. After mixing ml. of the solution of the dyewith g. of a silver bromide emulsion (containing about 30 g. of silverbromide per one kg. of emulsion), the mixture was applied to a glassplate. The dye was fixed in the emulsion'layer by a precipitant such asdiphenylguanidine (described in the specification of U.S. Pat.2,172,308). The light-sensitive plate was exposed through a step Wedge,developed in a developer containing N-methyl-paminophenol /2 sulfate andhydroquinone, and then fixed. The plate was then hardened by a dilutedsolution of formaldehyde and thereafter processed in a dye bleachingbath containing 30 ml. of concentrated hydrochloric acid, 30 g. ofpotassium bromide and 60 g. of thiourea per one liter of bleaching bath.After bleaching remaining silver in a copper sulfate bath stronglyacidified by hydrochloric acid, the plate was fixed in a conventionalmanner. A yellow dye image was obtained.

EXAMPLE 9 Into 300 ml. of a 10% aqueous gelatin solution, 2 g. of Cl.Acid Yellow 24 shown by structure (6) was dissolved. The colored gelatinsolution was applied to a dry-thickness of 3 microns to a silver halideemulsion layer of 7 microns dry-thickness coated on a glass plate. Whenthe light-sensitive plate was processed as in Example 1, a yellow imagewas obtained in the colored gelatin layer in proportion to the silverimage formed in the silver halide emulsion layer.

' EXAMPLE 10 A standard photographic light-sensitive black and Whitefilm was exposed, developed, and fixed in the conventional manner. Thefilm was dyed for about 20 minutes at room temperature in a 2% aqueoussolution of Cl. Acid Yellow 24 shown by structure (6). In this case, adyeing aid may be added as in standard dyeing techniques. After dyeing,the film was subjected to the dye bleaching and subsequent processingsas in Example 1 to provide a yellow image.

What is claimed is:

1. In a silver dye bleaching method which comprises exposing to light aphotographic light sensitive element comprising a silver halidecontaining'emulsion layer uniformly colored with at least onebleacha'ble nitro aryl dye, processing and subsequently bleaching saidelement, the improvement wherein said dye is a bleachable nitro aryl dyehaving as the chromophore a nitro group and as the auxochrome a memberselected from the group consisting of OX, wherein X represents a memberselected from the group consisting of a hydrogen atom, an alkali metal,/2 calcium and ammonium, and NHY, wherein Y represents a member selectedfrom the group consisting of a hydrogen atom, a lower alkyl group, asubstituted alkyl group, a. cyclic alkyl group, an aryl Z9 group and asubstituted .aryl. group,; said --NHY having the capability of forming a.ring together with a member selected from the group consisting of O andiwherein R is selected from the group consisting of an aryl group and asubstituted .arylgrofip, which is at the ortho position to NHY.

'2. A process as in "claim 1 wherein Y represents a substituted alkylgroup selected from the group consisting of an afninomethyl group and ahydroxyethyl group.

3. A process as in claim 1 wherein Y representsa substituted aryl groupselected from the group consisting of a hydroxyphenyl group and asulfonaphthyl group.

4. A process as in claim 1 wherein R represents a methoxyphenyl group.

5. A process as in claim 1 wherein the dye is nitrobenzene havin OX orNHY at the orthoposition to the nitro group. 1

6. A process as in claim wherein the dye is substituted with at leastone member selected from the group consisting of a nitro group, a loweralkyl group, an aryl group, a Substituted aryl group such as a;nitrophenyl group, an amino group, a eyano group, a halogen atom, acarboxyl group, a sulfonic acid group, SO R (wherein R represents amember selected from the group consisting of an aryl group and asubstitutd aryl group such as a nitrophenyl group),

(wherein R and R may be selected from the group consisting of a hydrogenatom, a lower alkyl group, a substituted alkyl group selected from thegroup consisting of an amino methyl group and a hydroxy ethyl group, acyclic alkyl group, an aryl group and a substituted aryl group such as ahydroxyphenyl group).

7. A process as in claim '5 wherein the dye is nitro naphthalene.

8. A process as in claim 6 wherein the dye is nitro naphthalene.

9. A process of obtaining color photographs by a silver dye bleachingmethod as described in claim 1, using 2. nitro dye having the formula:

10. A process of obtaining color photographs by a silver dye bleachingmethod as described in claim 1 using a nitro dye having the formula:

11. A process of obtaining color photographs by a silver dye bleachingmethod as described in claim 1 using a nitro dye having the formula:

12. A process of obtaining color photographs by a silver dye bleachingmethod as described in claim 1 using a nitro dye having the formula:

I QM H 13. A process of obtaining color photographs by a silver dyebleaching method as described in claim 1 using a nitro dye having theformula:

14. A process of obtaining color photographs by a silver dye bleachingmethod as described in claim 1 using a nitro dye having the formula:

16. The process as claimed in claim 1 wherein said nitro dye isincorporated in a photographic silverhalide light-sensitive emulsionlayer in said photographic lightsensitive element.

17. A process as in claim 16 wherein the nitro dye is used as a dye fordyeing a colloid in the photographic light-sensitive element so as toform the yellow image of a multiple layer light-sensitive element, saidcolloid being selected from the group consisting of gelatin andpolyvinyl alcohol.

18. A process as in claim 16 wherein a colloid for forming alight-sensitive layer in said photographic element is colored by thenitro dye and then mixed with a silver halide emulsion for subsequentapplication to a support.

19. A process as in claim 16 wherein a water soluble nitro dye is mixedin the sensitive emulsion layer as an aqueous solution thereof.

20. A process as in claim 16 wherein a water insoluble nitro dye isdispersed into the sensitive emulsion layer by using a dispersing agent.

21. A process as in claim 16 wherein a nitro dye soluble in an organicsolvent is formed into a solution, and the solution thus obtained ismixed with the sensitive photographic emulsion.

22. The process as claimed in claim 1 wherein said nitro dye isincorporated in a gelatin layer adjacent to 211 photographicsilver-halide light-sensitive emulsion ayer.

23. A process as in claim 22 wherein a water soluble nitro dye is mixedinto the gelatin emulsion by dissolving it in an aqueous gelatinsolution.

24. A process as in claim 22 wherein a water soluble nitro dye isdispersed into the gelatin emulsion by using a dispersing agent.

25. A process as in claim 22 wherein a nitro dye soluble in an organicsolvent is formed into a solution therewith and mixed with a gelatinsolution.

26. A process as in claim 22 wherein the organic solvent solution isemulsion dispersed in gelatin by using a surface active agent.

27. The process as claimed in claim 1 wherein, after exposing andprocessing, said bleaching of said nitro dye is accomplished bysubjecting said element to a dye bleaching bath.

28. A process as in claim 27 wherein the dye bleaching bath contains asolvent for silver and an alkali metal halide.

29. A process as in claim 27 wherein the dye bleaching bath contains, asa catalyst, a dye bleaching accelerator.

m sis- 99 I 5 NORMAN TORCHZIN, l ri mary. Examiner

